Im not quite sure what you were watching or reading... but in the video i watched, in the link above, he actually says some games cant be played on a touch screen. He didn't say that it wasn't a gaming platform. Besides, it's just his opinion lol
"I and other gamers will decide what we think are gaming platforms"
He's not suggesting that it isn't a gaming platform - he's just saying that not every game can be experienced as well as it potentially could on that device.
Perhaps it's a bit of reading between the lines, but the second comment to the post (on the blog itself, not here) reads "THANK YOU! THE iPHONE/iPOD IS NOT A GAMING DEVICE!", so I don't think I'm alone in reading that rant and walking away with the thought that the author is bitter about phones as a gaming platform, beyond just what his words literally say.
If that reading is incorrect, then I take solace in the fact that at least one other person was dumb enough to read it as I did.